Method of treating bones for the production of glue.



PATENTED FEB. ze, 1905.

E. R. HBWITT. METHQD 0F TRE'ATING Bums POR THEPRODUGTION 0F GLUE.

APPLICATION FILED IAB. 7, 1902.

im mm ltll'o. 783,784.

UNTTED STATES Patented February E3B, T905.

PATENT EErcE,

lVll-THOD 0F TREATING BONES FOR THE PRODUCTION OF GLUE.

SPECIFICATION forming part of Letters Patent No. 2783,784, datedFebruary 28, 1905.

Application filed March '7, 1902. Serial No. 97,138.

To rr/ZZ whom it may concern:

Be it known that I, EDWARD R. Hiawrrr, a

'citizen ot' the United States, residing` at Garden Uity, in the countyof Queens and State of New York, have inventedcertain new and use-FulImprovements in Methods of IreatingI Bones t'or the Production of Glue,oil which the following is a true and full description.

This invention relates to an improved method for producing' glue frombones by separating' the hard non-lutinous portions oi the bones fromthe glutinous portions by an improved treatment with sulfureus acid andsubsequently subjectingI the glutinous portion to a proper treatment toform a commercial glue therefrom.

The apparatus for carrying out my new process is illustrated in theaccompanying drawings, in whichm Figure l is an elevation of the vat inwhich the stock is treated. Fig. 2 is a diagrammatic illustration oi'the apparatus which may be employed for the relining treatment of theglueu liquor.

lhe invention may be described in detail as follows: After the boneshave been subjected to a short preliminary treatment, such as boiling,to remove the superh'cial impurities, such as grease and otherchemically Free matter not a part of the bone structure, they aresubjected tothe separating treatment. The acid used in the treatment olthe bones according to my process is preferably approximately atwelve-per-cent. solution ol" sullurous acid in water. The preparationol such a solution, as is well known, generates considerable heat. Vitis desirable,as Vfurther described hereinafter, to keep down thetemlierature during' the separating treatment. l therefore `form thenecessary mixture of sulfur-ous acid and water in any vessel or chamberadapted to the purpose and cool the mixture before it is applied to thebones. Vln my application, Serial No. 97,1137, tiled March 7, 1902, lhave described an apparatus adapted to be used in connection with thepresent method to recover the sulfurous acid and to again mix it withwater for a second application tothe bones. The present method is,however, entirely independent ot' the source of the acid used. It isonly necessary that the acid should be mixed with the water and theresulting' heat dissipated before application to the bones. Theseparatingl treatnnmt takes place in the vat V, (shown in Fig. 1,) thevat boingI adapted to rotate Vabout once a minute by any suitable means,such as the gears shown. About ten thousand pounds et bones are ii rstshovcled into the vat-V from a suitable platform (not shown) above themanhole in the vat, and the previously-prepared cold aqueous sulfur-ousacid is introduced on the boues in the vat V through the axial pipe l?,in suflicient quantity to cover the bones. .lhe pipel has an el bowextending;l

down below the screen M, said pipe and elbow i beingl revolved with thevat. There will be immediately a l,generation oi a large amount oiIcarbon dioxid, which carries with itconsider able sulfurous acid. Theacid is saved and d anger of explosion is averted by providing' exitthrough the elbowed axial pipe (L), which is stationary and does notrevolve with the vat, the result beingl that its opening is always atthe open space at the top of the vat above the bones and aqueous acid.The pipe Q should be connected with the sult'ui'ous-acid tower (notshown) where the carbon dioxid is permitted to escape, while thesul'liurous acid mixes with the like acid which is made in the tower.The rotation oi the vat V causes the mass o'll stock to be tumbled aboutin the aqueous acid, thus preventing` the collecting` oli bubbles olcarbon dioxid on. the surface ol the bones and preventing' the boneslrom becoming' closely packed together, thereby facilitartinel theaction of the acid and accomplishing' the sepa ration in one-third thetime required in a stationary vat. 'lhis reduces the number oltreatments and the amount ol` acid which would otherwise be required. Atthe same time that the carbon dioxid is liberated the acid begins tocombine with the phosphates and sullites in the bones. The excess ol.water olf the aqueous acid serves as a dialyzing' agent to carry theacid into the imiermost recesses ol the bones, to act on every portionet the calcium contained therein, to kill the bacteria, and to partiallyhydrate the ,gelatinous sub stances to facilitate their subsequentdissolu tion in hot water. it also serves as a solvent TOC for thccalcium salts which are formed by the combination with the acid. Thischemical combination causes a rise in temperature, which would be overTIC Fahrenheit, the temperature at which the gelatin would ilow and bemixed with the solution if the aqueous 1 The i g'elatin will flow veryfreely at 80@ Fahreni heit and its quality be injuriously affected atacid had not been previously cooled.

such high temperature, and I have found that the aqueous acid should bepreviously cooled to a temperature (dependent upon quantitativeconditions) which will result in keeping the temperature of the aciddown below TOO Fahrenheit during its action on the bones. It isimportant not only that each successive separating treatment should beconducted at a low temperature, but that it be terminated speedily aspossible, as the tendency of the gelatin to render increases directly inproportion to the rise in temperature caused by the extended duration ofeach treatment. The time might oi' course be shortened by increasing'the streng'th oil the aqueous acid; but if this is made too strong itwill attack the gelatinous substances and injure the quality oi thelinal product or in extreme cases result in decomposition. Furthermore,it is impracticable to make a very strong aqueous acid on l account ofthe extended time necessary for the absorption of large quantities ofthe gas by water at atmospheric pressure, which is the ln'essureat whichthis work can be best done in practice. The water will absorb readilyonly eleven or twelve per cent. ot the acid at ordinary temperatures andpressures. On the other hand, it' the aqueous acid be made very weak itwill not combine with very large quantities of the calcium in the bones,and it will not be economical to separate the acid-gas from the solutionso weakly saturated with the resulting salts for succeeding applicationslto the bones, owing to the large amount of water and the consequentincrease in the amount of heat necessary for the subsequent separationofthe acid-gas. It is between these two limits` therefore. that I havefound the separating treatment can be best carried out in a practicaland commercial manner, and, as stated above, the aqueous acid shouldcontain about twelve per cent. ol acid. At.- ter the aqueous acid hasacted for a short time its tendency to combine with the calcium oi thebones is partially satisfied, and I have found that after this quicksaturation to a ce1'- tain degree it takes a very much long'erproportionate time for the solution to be entirely saturated. It isdisadvantageous to attempt to continue the separation of the gelatin byleaving the solution on the bones after the acid ceases to combinereadily with the calcium, owing' to the fact that if this were done thetemperature would reach too high a degree and the gelatin would flow orits quality be impaired, although the extraction ot' the quantity ot'the acid to remain on the bones a longer time without a'ecting' theg'elatinous substances than it could otherwise and enables the aqueousacid to combine with a larger amount ot' the calcium before the solutionbecomes hot enough to ati'ect the gelatin. Furthermore, it the solutionwere left on the bones after it had become fully saturated with saltsthe latter would precipitate and be deposited in the pores of the bonesin the Jform of a much less readily soluble precipitate, so that furtherseparation of the gelatin would not be possible within a reasonablyshort time at the low temperature andwith the relatively weak aqueousacid required. Itis, however, quite important that the solution shouldbe as nearly saturated with the salts as practicable in order that theamount of solution from which the acid-gas is to be separated for thesucceeding' treatmentmay be as small as possible. I have found that it'an aqueous acid of a strength (about twelve per cent.) which it ispracticable to prepare in a short time is applied to a mass oi' bonesthe gelatinous substances will not be completely separated even whensuch a solution is completely saturated. In order. to prevent thedeposition of insoluble salts which would plug u p the pores of thebones and in order to shortenA the time of each separating treatment bynot leaving the solution on the bones after the acid begins to combinebut slowly with the calcium, I draw olf the partially-saturated solutionby pumping it through the pipe P into the storage-Vat V', and thenanother quantity of aqueous acid, formed as described, is introduced onthe partially-treated bones in the vat V through the pipe P by the valveB from the tank F to effect a continuation of the separation of thenon-g'elatinous substance. This second quantity of aqueous acid may beformed from the gas which is liberated from the solution containing' thecalcium salts instead of the gas from the tower (in which g'as is madein any well-known manner) by heatingl the said solution directly withopen steam in a manner described in my application, Serial No. 97,137,tiled March 7, 1902. This second treatment results in the furtherseparation of the hard non-g'elatinous substances, and l lind that it isdesirable to repeat the separating treatment several times untilsubstantially all ot' the phosphates and sultites are freed fromchemical combination in the bones. The quantity of aqueous acid appliedin each successive treatment or run. as I call it in practice, issaturated to a less degree than the previous one, owing to thegradually-increasing dialytic resistance of the increased exposed massof the gelatinous substances. Vhen a certain run is reached wherein thesolution is so weakly saturated that the cost of separation oftheacid-gas from 1t would be relatively too great,

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rasata owing to the excess of water and the necessity for theapplication of an excessive amount of heat, the liquor of this run isused for the first application to a fresh quantity of bones theseparation of the gelatinous substance from which has not been begun. Bythus employing a partially-saturated acid solution upon the fresh massof bones a too sudden evolution of carbonio-acid gas is prevented, thusavoiding the danger from explosion which would exist if there wereapplied to the boues an unsaturated solution containing onlya smallpercentage of acid. Since in a fresh quantity of bones there are largeexposed surfaces of the calcium salts in combination, even thispartially-saturated solution from a previous treatment will quicklybecome saturated to thedegree at which separation of the acid-gas fromit can be cheaply accomplished and at which it should be drawn oif fromthe bones. l have found that by thus using for the first treatment ofthe bones the liquor which had been used for the later treatment ofother bones there is required about thirty per cent. less weight of theaqueous acid for properly treating a given weight of bones. .lhis ofcourse greatly reduces the amount of the aqueous acid from which it isnecessary to separate the acid-gas. This amount is nearly as low as thetheoretical amount required,\vliich shows that the operation is nearlyperfect. l f the separating treatments are conducted as described, aboutninety-tive per cent. of the bone-ash will be carried oil", and henceonly a very small portion of the ash will remain in theI gelatinouscartilage.

The storage-vat V should be of suilicient capacity to contain successivecharges of the solution drawn oil'l from the bones in the vat V, so thatthe pump U (shown in the lower right-hand corner of Fig. 3) may beoperated continuously, if desired. The pump U forces the solution fromthe storage-vat V into the apparatus where the acid-gas is separatedfrom the solution, and subsequently a cool aqueous acid is made in themanner described in my application, Serial N o. 97,137, above referredto, in preparation for the continuation of the separation of thenon-gelatinous substances Afrom the bones.

After the several successive treatments of the bones with the aqueousacid have been completed the gelatinous substances remain in the vat Vin the form of yielding springy pieces resembling soft rubber inconsistency. A quantity of fresh water is then introduced into the vat Vthrough the pipe P, and the vat is rotated for the purpose of washingthe bones to remove the excess of acid, or the bones may be partiallyneutralized for the same purpose. A little acid should be left to serveas a vehicle to complete during the glue-rendering operation thehydration which is begun during the separating treatments, so'that thegelati nous substances will dissolve more quickly.

The mass of bones after being washed or neutralized is then` ready forthe glue-remlering operation, wherein the gelatinous substances are putin solution. The cartilage resultingl from the separating treatmentsbesides being in perfect condition for the gl 11e-rendering operation isalso valuable as a commercial product to be sold to the trade 'forglue-rendering at some future time. To render the gelatineus substances,they are put into solution in water below boiling temiierature, whichresults in a product of greatly-improved quality. Hitherto it has beencustomary to boil the water in which the gelatiuous substances of thebones are put in solution and to prolong the operation for aconsiderable time. This has been necessary because the gelatinoussubstances have not been entirely separated from the calcium, andtherefore could not have been partially hydrated throughout for thepurpose of hastening the dissolution of the tissues. The raising ofthousands of pounds of stock to boiling tenuiierature naturally requiredconsiderable ti me when the stoel: had not been previously hydrated. Theboiling temperature also served to kill the bacteria, which must beaccomplished at some time, as they would otherwise injure the teusilestrength and darken the color of the glue and shorten its life after ithas been treated fQr use in practice with water, which would serve topropagate the bacteria. A temperature in water of at least 160CFahrenheit is necessary to kill the bacteria. l have found that atemperature of 150"J and higher will injure the quality of the glue insolution in an acid state and that a prolongation of the renderingoperation will permit considerable bacteriological rottingl to takeplace if there are any bacteria in the stock when it goes to therendering operation. It is of course advantageous to quick rendering toconduct the operation at a temperature as near 150O as is possiblewithout injuring the quality of. the resulting product. Since thegelatinous substances separated from the bon es in accordance with thisinvention are substantially free from calcium and are partially hydratedthroughout by the excess of water in the aqueous acid, ll am enabled toput the substances in solution in water which is not boiling, but whichis preferably heated up to nearly 150@ Fahrenheit. rlhe slight amount ofacid left in the stock from the separating treatments will not injurethe glue, I have found, if there is no more acid than the glue willcombine with. On the contrary, I have found that such a small amount ofacid is advantageous as a vehicle to assist in the hydration of thesubstances, and thus hasten the rendering operation. 1f there is anexcess of acid, the product will be brittle in the jelly. The product ofthe rendering operation is a glue solution containing variousil'npurities which could not conveniently be removed pre- IOO IIO

viously. This solution is drawn off from the rotating vat V through thevalve H into the clarifying-tank I. rThe pipe controlled by the valve Hleads into the rotating vat beneath the screen M, so that the largerimpurities will not be transferred to the tank I. An alkaline earth isadded to the glue solution in the tank I and is thoroughly mixed bymeans of the stirrers J, operated by suitable pulleys. This operationneutralizes the solution and precipitates the impurities, which arefinally separated from the pure glue solution by a filter-press K, towhich the solution, with the impurities in suspension, is forced by thepump O. The pure glue solution is then ready to be evaporated, jellied,dried, and cut in any well-known manner.

I am aware of the English Patents N o. 4,356 of 1888 to Lake, No. 15,664of 1885 to Schroeder, No. 1,914 of 1863 to Gerland, No. 1,422 of 1868 toGerland, No. 3,820 of 1814 to Mertian, No. 7,661 of 1888 to Rattray, andof the United States patent to Schroeder, No. 518,861.

I claim as my invention- 1. The improvement inthe art of treating bonesfor the production of glue, which consists in subjecting the bones totreatment with successive quantities of combined sulfurous acid andwater, from which the heat of combination has previously beendissipated, and terminating each treatment before the bone saltsprecipitate and before the temperature rises above 740 Fahrenheit,substantially as described.

2. The method of removing bone salts from bones for the production ofglue, which consists in ooding the bones with a solvent comprising'combined sulfurous acid and water, drawing off the solvent from thebones before the bone salts dissolved therein precipitate, whereby aportion of the bone salts is removed from the bones, again ooding thebones with a second quantity of the said solvent, and again withdrawingthe solvent before the bone salts precipitate, for the further removalof the bone salts, and continuing such treatment until the bone saltsare sufficiently removed, substantially as described.

3. The method of removing bone salts from bones for the production ofglue, which consists in flooding the bones with a solvent comprisingcombined sulfurous acid and water from .which the heat of combinationhas previously been dissipated, removing the solvent before thetemperature rises above 740 Fahrenheit, whereby a portion of the bonesalts is removed, again ooding the bones with a second quantity of thesaid solvent, and again withdrawingthe solvent before the temperaturerises above 74s@ Fahrenheit, for the further removal of the bone salts,and continuing' such treatment until the boue salts are suiiicientlyremoved, substantially as described.

In witness whereof I have hereunto signed my name this 21st day ofFebruary, 1902.

EDINARD R. HEWITT.

In presence of- JAMES J. GosGRovE, W. H. BERRIGAN.

